Use of positron emission tomography (PET) showed no association with two-year survival in lung and esophageal cancer patients and may possibly be overused in the hopes of detecting cancer recurrence, according to a study published February 22 in the JNCI: Journal of the National Cancer Institute.

PET scans, which are primarily used in cancer patients for staging, restaging, and monitoring patients' response, are also frequently used to detect recurrence in asymptomatic patients. Despite this frequent secondary use, there has been little evidence showing that PET scans improve survival.

In order to determine the efficacy of PET scans for recurrence detection, Mark A. Healy, M.D., Department of Surgery, Center for Healthcare Outcomes & Policy, University of Michigan, and colleagues, looked at the national Surveillance, Epidemiology, and End Results (SEER) and Medicare-linked data of 101,598 patients with primary lung and esophageal cancers from 2005 to 2009, with follow-up through 2011. The researchers specifically looked at lung and esophageal cancers due to their comparable poor diagnoses and general anatomic location

Using the Medicare claims, the researchers looked at PET utilization in person-years, and looked at patient and tumor characteristics in order to calculate risk-adjusted two-year survival. The researchers then looked at hospitals by quintiles of PET utilization for adjusted two-year survival analysis.

The researchers found a statistically significant difference in the use of PET in the lowest vs highest PET utilizing hospitals. Despite this variation, the researchers found no association between the use of PET and two-year survival. "This combination of hospital-based variation without survival benefit suggests potential overuse and that efforts to decrease such overuse are warranted," the authors write. "Providers must take note of available data when making clinical imaging decisions to avoid unnecessary overuse."